Thoughts on cotton weed control… Jeremy Kichler Colquitt County Agent
BURNDOWN: Palmer amaranth must not be emerged when planting, regardless of cotton cultivar planted. Standard programs using
Valor (before Palmer emergence), Direx, and Gramoxone + Direx are advised. Dicamba or 2,4-D would be beneficial for primrose, horseweed, and radish (2,4-D is much more effective on radish). All weeds and cover crops with the exception of cereal grains should be killed > 10 d before planting. No plant back interval exists for XtendiMax or Engenia in XtendFlex cotton; other cultivars may be planted 30 d after 1” of rainfall. No plant back interval exists for Enlist Duo or Enlist One in Enlist cotton; other cultivars may be planted 30 d after application, and 0.5” of irrigation between application and planting is beneficial.
Preemergence (PRE) applications: Include 2 active ingredients for better control, less crop injury, and less herbicide resistance development. Below are some choices of preemergence treatments. 1) Brake + Reflex 2) Brake + Warrant 3) Direx + Warrant 4) Reflex + Direx 5) Reflex + Warrant HERBICIDE RATES ASSUME TIMELY SEQUENTIAL POST APPLICATIONS AND DIRECTED LAYBY
1) Brake contains fluridone; 1 pt/A is an effective rate in mix with other herbicides. Fluridone requires significant rain/irrigation to become fully active.
2) Warrant: For most soils, 32-40 oz/A is in order. Effective on most grasses, pigweeds and is essential for spiderwort.
3) Direx: For most soils the ideal rate is 10-20 oz/A; lower rates on sands or under intense irrigation. Avoid diuron PRE if it was applied within 14 d of planting as a burndown.
4) Reflex: For most soils, ideal rate is 1012 oz/A when in these tank mixtures. Reflex mixtures are the most effective option for Palmer.
NOTE: Add paraquat if pigweed is emerged; a jar test is strongly advised if mixing with Brake